A state appeals court has upheld more than $300,000 in damages for a Hayward truck driver who was fired after complaining about having to lift a heavy tractor-trailer gate that had caused back injuries to him and other truckers.

Howard Sanders worked for Central Freight Lines for seven years until April 2008, when he was assigned to a loaded rig with a lift gate weighing between 150 and 200 pounds. Sanders had strained his back trying to lift the same type of gate in the past, and he asked his supervisor to switch him to another tractor-trailer in the yard, the court said. The terminal manager then accused him of insubordination and fired him.

The company later claimed that Sanders was dismissed for failing to report his earlier injury. But after a nonjury trial in 2011, Alameda County Superior Court Judge Yvonne Gonzalez Rogers - now a federal judge - ruled that he had been illegally fired for protesting unsafe conditions. Several other drivers testified at the trial that the gate was too heavy to lift with a straight back, and two said they had also been injured.

Gonzalez Rogers awarded Sanders $306,000 in damages, mostly for lost wages and benefits. The First District Court of Appeal upheld her verdict Thursday, saying the evidence showed that the company had retaliated against Sanders for his "valid protestation about a dangerous piece of trucking equipment."

Sanders, who lives in San Jose, now works for another trucking company with lower pay, said his lawyer, Robert Blumenthal. Central Freight Lines' attorney was unavailable for comment.